A large body of research currently exists on crowding and its effects on performance, physiological functioning and social and physical pathology. From the point of view of urban studies, and particularly the development of national or local housing and neighborhood standards and goals, this work is deficient in two ways. First, a large number of alternative definitions of crowding have been used almost indiscriminately with no empirical testing of the interrelationships among definitions or the effects of alternative definitions on housing and neighborhood outcomes. Second, the relevance of this literature to urban studies is lacking and the extrapolation of results as inputs to the development of housing and neighborhood policies is hazardous. This proposal seeks support for a preliminary empirical investigation of alternative definitions of crowding in the residential environment. Using the statistical analysis techniques for correlation and regression, tests for the interchangeability among a range of specific definitions of residential crowding variables, and the different effects of alternative definitions on important housing and neighborhood outcomes (i.e., satisfaction, mobility, and cost) will be performed. Three data sets will be used: the three most recent waves of the Panel Study of Income Dynamics, which will allow testing on a national cross-section as well as an intensive look at the poor; the Detroit Quality of Life study, which provides a close look at a large, old central city and its surrounding rings; and the Ann Arbor Rental Housing study data, which includes the most complete range of crowding and housing quality variables, lets us look at one sector of a rather unique housing market, and has already produced interesting preliminary results. Appropriate statistical controls for demographic, socio-economic and other contextual variables will be used in all multivariate analyses. When identical equations are possible, comparisons across data bases as well as examination within a particular data base, will be presented.